In a radio communication system, events (failures) that block normal operation of the system sometimes occur, such as device malfunction or application related trouble. In order to achieve a stable radio communication system, the occurrence of a failure needs to be detected rapidly, and the system needs to be restored.
During data transfer, when a base station detects packet loss or transfer delay, which are caused by failure, the base station determines that communication is problematic. The base station then notifies a monitoring center (for example, an Element Management System (EMS)) of an alarm containing error information. The occurrence of a failure is detected via the alarm. If the very device that determines communication to be problematic has deteriorated or is malfunctioning, however, the monitoring center might not be notified of an alarm, despite the occurrence of a failure. If notification of an alarm is not provided, the occurrence of the failure is not detected. Such failure that is not detected upon occurrence is referred to as silent failure. Silent failure is discovered not via an alarm, but rather by circumstances such as degradation in performance, network delays or loss of communication, and greater effort and cost are required to recover from a silent failure than from a regular failure.
To address this problem, a method (for example, see Patent Literature 1) has been proposed whereby a mobile station, rather than a base station, actively transmits error information on communication problems to a monitoring center (management device). With this method, when a communication problem occurs, the mobile station accumulates error information (by time and place of occurrence and cause of the communication problem) in a storage device within the mobile station. Subsequently, when communication with the base station is successful, the mobile station transfers the accumulated error information to the management device via the base station. The management device uses the received error information to perform statistical processing by time, place and cause of the communication problem. The method in Patent Literature 1 thus allows the management device to identify a base station with a high probability of failure through statistical processing based on error information from the mobile station.